The invention relates to a device for moving a medical apparatus in a controlled manner as claimed in the precharacterising part of claim 1 and to a method for moving a medical apparatus in a controlled manner as claimed in the precharacterising part of claim 25.
X-ray apparatuses, particularly those having a C-shaped bow provided with an X-ray source mounted on one end and an X-ray receiver mounted on the other end thereof (in the following briefly referred to as xe2x80x9cC-bowxe2x80x9d) are part of the standard operating-theatre equipment in emergency surgery. Apparatuses of this type serve for intra-operative imaging purposes, making it possible to control the repositioning manoeuvres necessary for the treatment of bone fractures and to monitor the insertion of implants stabilising the fracture. When the C-bow is used in combination with modern surgical navigation systems, a continuous visualisation of the surgical procedure is made possible by means of fluoroscopic images which are created intra-operatively and may be stored in a computer.
As the procedure described above implies working with X-rays in the presence of persons, i.e. the patient and the operating-room staff, the positioning of the X-ray apparatus should be carried out in such a way as to avoid long periods of fluoroscopic exposure, in other words the exact position should be found right at the first attempt. However, according to the usual practice, the C-bow in the operating theatre is not moved by the operating surgeon him-/herself but by a member of the operating-room staff. The mere communication between the operating surgeon and said member of the operating-room staff concerning the execution of a specific movement of the apparatus relative to the patient may give rise to numerous errors. Often, the C-bow is used after an individual step of an operative procedure in order to control and document the success of the intervention. If a correction of the provisional result of an intervention is necessary, the C-bow must be removed again from the right position which had just been found with difficulty, as the apparatus would otherwise be in the way of the operating surgeon performing the correction on the implant or on the fracture site. In order to perform the control which is subsequently necessary, the C-bow must be brought into the xe2x80x9crightxe2x80x9d position again, which had already been determined before. This may often lead to long periods of exposure before the image intensifier will generate the right image. A C-bow provided with a xe2x80x9cmemoryxe2x80x9d for positions which have once been correctly adjusted would represent a considerable improvement.
A drive device for different vehicles comprising modular, motor driven and controllable rollers is known from WO 98/19875 GRANT. The drive device is controllable by means of a computer having wireless access e.g. to road maps or positioning systems.
A medical system provided with rollers is known from DE 197 01 346 SIEMENS. This known medical system is provided with controlling means for the rollers realized by means of rails and comprises a remote control unit.
Another medical device having motor driven and controllable rollers is known from U.S. Pat. No. 4,589,126 AUGUSTSSON. The control of the drive devices is realized in one embodiment of this known device by means of a computer.
Disadvantageous at these known device is that the computer serving for the control of the drive devices has to be programmed before the treatment or has to be fed with control instructions through an external xe2x80x9cfixxe2x80x9d positioning system.
The invention is intended to provide a remedy for this. It is accordingly an object of the invention to create a device for moving a medical apparatus, particularly an X-ray apparatus, in a controlled manner.
According to the invention, this object is achieved by means of a device for moving a medical apparatus, particularly an X-ray apparatus, in a controlled manner which shows the features of claim 1, and by a method for moving a medical apparatus in a controlled manner which shows the features of claim 25.
Variant without Surgical Navigation System (Basis Version)
The advantage achieved by this consists in the fact that here the X-ray apparatus is moved by the operating surgeon him-/herself. There is no need any more for a second person interpreting and executing the instructions of the operating surgeon which the latter has encoded in his own coordinate system.
The inventive device for moving a medical apparatus in a controlled manner enables a controllable positioning of an apparatus, in particular an X-ray apparatus, in the two dimensions (x/y) of a plane, especially a plane extending parallel to the floor of the operating theatre. The device comprises at least three motor-driven rollers provided with a first axis of rotation extending parallel to said plane and intersecting the centre of the roller, and a second axis of rotation extending perpendicularly to said plane and lying in the plane of the roller or parallel thereto. The rollers are fixedly positioned relative to each other. Each of the rollers is provided with a first drive device by means of which the roller may be rotated about the first axis of rotation and with a second drive device by means of which the roller may be rotated about the second axis of rotation in order to change its direction of travel.
The rollers may be fixed either directly on the medical apparatus via their second axes of rotation or may be fixed, via their second axes of rotation, on a frame serving as a platform for the medical apparatus. The version with a platform is particularly suitable for retrofitting existing apparatuses, whereas the version with the rollers fixed directly on the apparatus will rather be taken into consideration for new apparatuses.
Stepper motors, in particular electronically controllable stepper motors, may be used as first and second drive devices. Stepper motors based on digital drive technology are equally possible. Further details concerning stepper motors of this type may be found, for example, in
Dubbel; Taschenbuch fxc3xcr den Maschinenbau (Pocket Book of Mechanical Engineering); Eds. W. Beitz and K.-H. Grote; Springer Verlag, 19th edition, 1997; Pages: T9 and V29.
The X-ray apparatus according to the invention is preferably realised in the form of a C-bow which is mounted on the inventive device by means of a pedestal. C-bows are usually provided, in addition to the two directions of displacement defined by the plane extending parallel to the floor of the operating theatre, with further axes of motion permitting a movement of the C-bow relative to the displaceable pedestal, which merely serves for displacing the apparatus parallel to the floor. For the handling of the C-bow, at least one linear movement of the C-bow parallel to an axis extending vertically to the floor of the operating theatre (z-axis) as well as motions of rotation about at least two further axes are necessary.
These movements of the C-bow are equally performed in a motor-driven manner. The drive devices for these motions may equally be stepper motors, as described above for the rollers of the inventive device. Linear movements are suitably performed by linear motors such as those described in detail in Dubbel; Taschenbuch fxc3xcr den Maschinenbau (Pocket Book of Mechanical Engineering); Eds. W. Beitz and K.-H. Grote; Springer Verlag, 19th edition, 1997; Pages: T9 and V31.
All the drives mentioned above may either be subject to the direct visual control of the operating surgeon or be controlled by retrieval of stored data relating to a previously occupied position or projection.
1. In this embodiment of the X-ray apparatus according to the invention, the initial positioning of the C-bow is carried out by the operating surgeon under direct visual control by either of the following means:
a) by using a preferably wireless, sterilisable control console; or
b) by voice control (e.g. using the following instructions: forward, backward, to the right, to the left, fast, slowly, turn about axis A,B,C).
2. For permitting a positioning of the C-bow by retrieval of stored data, the X-ray apparatus according to the invention comprises in addition a computer equipped with at least a data memory, a display screen, and a keyboard. In order to reproduce a previously occupied projection, it is thus possible with the aid of the computer to store the lengths and the temporal succession of the displacements performed during the initial positioning in the data memory and to reproduce them by activating a control function stored in the computer. The activation of the control function may in turn be performed either by means of the control console or by voice control (e.g. using the instructions: position 1, position 2).
The advantage achieved by the X-ray apparatus according to the invention consists in the fact that the positions and projections occupied by the C-bow are storable and can thus be automatically reproduced from any given position by the retrieval of the stored data. This is of advantage, for example, for monitoring tasks to be performed upon completion of corrective work done on an implant or a bone fracture in the course of which the C-bow has been removed from its position so as not to be in the way of the operating surgeon. The control device of the C-bow is thus provided with a xe2x80x9cmemory functionxe2x80x9d concerning previously adjusted projections. Positions and projections of the C-bow relative to the patient that have once been intra-operatively defined may, therefore, be reproduced after completion of further surgery any number of times without necessity of additional fluoroscopic controls to determine the right positioning. In addition, the computer-controlled embodiment permits to visualise the planned displacement of the C-bow on the display screen of the computer, which makes it possible to avoid collisions with objects present in the operating theatre that might otherwise occur during the automatic positioning of the C-bow.
C-bow with Combined Surgical Navigation System
In a further embodiment of the X-ray apparatus according to the invention, said X-ray apparatus is run in combination with a surgical navigation system. Such surgical navigation systems comprise at least one computer equipped with a data memory and with adequate operator""s controls as well as a preferably optoelectronic position detector for detecting the position of optical markers in a three-dimensional coordinate system within the operating theatre. As a surgical navigation system, an apparatus called xe2x80x9cSurgigatexe2x80x9d may be used, which is put on the market by the company MEDIVISION, Oberdorf, Switzerland. Often, such navigation systems function in combination with an optoelectronic position detector, for example the commercially availably apparatus Optotrak 3020 (three-dimensional motion measurement system) by Northern Digital, Ontario, Canada. The tasks of the computer controlling the drive devices of the C-bow may here be fulfilled by the computer that is integrated in the navigation system. For permitting the detection of the position and projection of the C-bow, said C-bow is provided with at least three non-collinear, optical markers, preferably LEDs (light emitting diodes) or IREDs (infrared light-emitting diodes). The positions of the optical markers within the three-dimensional coordinate system of the operating theatre is measured by the optoelectronic position detector and the coordinates thus obtained are stored in the data memory of the computer. From the positions of all markers, the position and projection of the C-bow in the operating theatre can be calculated by the computer.
In order to initially move the C-bow into a desired position, the system may be provided with an additional integrated control device (similarly to the embodiment without a combined surgical navigation system) intended for realising the first, or primary positioning of the C-bow.
This additional control device may optionally be realised by one of the following means:
a) vocal control of the C-bow via voice input;
b) control of the C-bow via a sterile control console (virtual keyboard) which may be integrated in the surgical navigation system; and
c) control of the C-bow by means of a pointer provided with optical markers.
The pointer according to c) comprises at least three optical, non-collinear markers, preferably LEDs (light-emitting diodes) or IREDs (infrared light-emitting diodes), which are fixed on a rod. The pointer is oriented by the operating surgeon in such a way relative to the patient that the longitudinal axis of the rod simulates the central X-ray of the C-bow. In order to define the position and orientation of the pointer, the three-dimensional positions of the optical markers are measured by means of the measuring device and the position and orientation of the pointer is subsequently determined by the computer. The computer also permits to determine a plane within a three-dimensional space which extends perpendicularly to the longitudinal axis of the pointer. This plane defines the desired projection plane for the primary positioning of the C-bow. Subsequently, the X-ray apparatus is given the instruction to occupy the position and projection thus defined.
In the embodiment just described, the positions and projections occupied by the C-bow may equally be stored in the computer, which makes it possible, by a later retrieval of the corresponding data, to reproduce the positions and projections previously occupied by the C-bow.
The utilisation of a surgical navigation system with an integrated position detector offers in addition the possibility of applying a reference base to a patient""s body which is provided with at least three non-collinear markers. Thus, it is possible to measure intra-operative changes in the position of the patient by measuring the positions of these markers and to store the modified position of the reference base in the data memory of the computer. Assuming that after the patient has been moved to a modified, second position within the operating theatre an X-ray photograph is to be taken the projection plane of which should correspond to that of an X-ray photograph taken previously while the patient had occupied the first position, it is possible, by means of the computer, to perform a coordinate transformation, calculating the position and projection of the C-bow and moving the C-bow into said position and projection which makes it possible, while the patient occupies the second position, to take an X-ray photograph in a projection plane corresponding to that of the X-ray photograph taken while the patient had occupied the first position. In this way, an identical image plane can be reproduced in spite of possible movements of the reference bases, which may occur, for example, during fracture reduction. In other words, this embodiment of the X-ray apparatus according to the invention allows for possible movements of the patient when reproducing stored projections.
For supervision purposes, it is desirable to have a possibility of reproducing the position and projection of the C-bow which is identical to a previously occupied position and projection. This may be realised by combining the computer with the additional control device of the C-bow mentioned above. As in the above example, the input of the control instructions for this additional control device may optionally be realised by one of the following means:
a) control of the C-bow via voice input;
b) control of the C-bow via a sterile control console (virtual keyboard) which may be integrated in the surgical navigation system; and
c) control of the C-bow by means of a pointer provided with optical markers.
The advantages achieved by the present invention consist essentially in the fact that the device according to the invention makes it possible to use the image intensifier in the emergency surgery operating theatre in the usual way while permitting it with the aid of the control device to occupy positions that will yield immediately the desired image plane and to reproduce these positions after completion of further surgery any number of times by retrieval of stored data.
The inventive method for moving a medical apparatus, particularly an X-ray apparatus, in a controlled manner by means of one of the devices described above comprises the following procedure steps:
A) input by the operator of an instruction to move the apparatus to a desired position;
B) transformation of this instruction into control signals by means of a control device;
C) transmission of these control signals to the drive devices mounted on the device;
D) displacement of the movable elements to the desired position by means of the drive devices.
The computer input of the instruction by the operator may be realised by means of a hand-operated control console, by voice control, or via a keyboard or a mouse.
The utilisation of a computer makes it possible to store any position occupied by the apparatus in the data memory of the computer, the position of the apparatus being calculable by the computer and storable in the data memory once the lengths and the temporal succession of the displacements of the movable elements have been determined.
If an optoelectronic position detector is used, said position, instead of being calculated, may also be determined by measuring the positions of optical markers fixed to the apparatus via the optoelectronic position detector and subsequently be stored in the data memory.
If the device is used in combination with a computer, it presents the advantage that a previously occupied position of the apparatus may be reproduced by activating a control function and retrieving the data stored in the data memory.
In the following, the invention and improvements of the invention will be illustrated in greater detail with reference to the partially diagrammatic representations of several embodiments.